Solar cells are known to provide a voltage which is limited by the energy gap of the semiconductor employed, this voltage being, as a rule, approximately 50 to 80% of the energy gap. For example, silicon solar cells, having a Si energy gap of 1.1 eV, provide a voltage of approximately 0.6 V under open circuit conditions. In practice, this low voltage of the solar cells is extremely inconvenient, since a higher voltage is demanded for every possible application, which means that a row of solar cells must always be connected in series. The tedious interconnection of each individual cells gives rise to an appreciable proportion of the cost of the complete system.
The present invention provides a solar cell structure which enables many cells to be connected in series on one substrate, in an integrated form. Using this structure, it is possible to satisfy the requirements of many applications with only one solar cell and, in the case of large systems, to decrease the effort involved in interconnection by a significant amount.